Vehicle communicaton method and system, function identifying system, and electronic control unit

ABSTRACT

In a vehicle communication system, a first identifier is uniquely assigned to at least one function for vehicle control, the at least one function is installed in at least one of a plurality of control units. An identifying unit identifies that a target function uniquely assigned with a target identifier is installed in which of the control units based on the first identifier and the target identifier.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on Japanese Patent Application 2005-226881filed on Aug. 4, 2005. This application claims the benefit of priorityfrom the Japanese Patent Application, so that the descriptions of whichare all incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to vehicle communication methods andsystems including a plurality of control units installed in a vehicleand an in-vehicle communication network that communicably links theplurality of control units to each other. More particularly, the presentinvention relates to such vehicle communication methods and systems,which are designed such that diagnosis monitoring devices arecommunicably linkable to the in-vehicle communication network.

BACKGROUND OF THE INVENTION

Conventional vehicle communication systems, in order to send a messageto a control unit, are designed to attach, to the message to be sent, anaddress identifying the control unit.

In addition, in vehicle diagnosis monitoring, an operator communicablyconnects, to an in-vehicle communication network, a diagnosis monitoringdevice, such as a diagnosis monitoring tool. Next, the operator operatesan enter key and the like of the diagnosis monitoring device to enter,into the diagnosis monitoring device, information indicative of acontrol unit (target control unit) in which a target function isinstalled beforehand and of descriptions associated with diagnosismonitoring of the target function. The descriptions are to instruct thetarget control unit what the operator wants to monitor and diagnoseregarding the target function.

In response to the information entry, the diagnosis monitoring devicesends, to the target control unit, request messages identifying thetarget control device as its destination and requesting it to executediagnosis monitoring of the target function in accordance with thedescriptions.

Note that the request messages for diagnosis monitoring include a datarequest message that requests a target control unit to execute afunction of returning control data stored therein and/or a drive requestmessage that requests a target control unit to execute a function offorcibly driving an actuator. The actuator is configured to putin-vehicle devices into automatic action, such as force or motion.

Techniques associated with routers that connect a plurality of differentnetworks to each other are disclosed in European Unexamined PatentPublication No. EP1039725A2 corresponding Japanese Unexamined PatentPublication No. 2000-244549.

In the conventional vehicle diagnosis monitoring set forth above, anoperator to manipulate the diagnosis monitoring device, in other words,an operator to perform vehicle diagnosis monitoring needs to previouslygrasp which functions are installed in advance in which of the controlunits. This may cause the diagnosis monitoring work to becomecomplicated.

Specifically, hardware standardization among communication systemsinstalled in vehicles is being promoted, which produces an improvementin the portability of applications to realize various types offunctions.

For these reasons, even if the functions are the same as each other,they may be installed in different control units depending on thevehicle models. In addition, even if vehicles have the same model,depending on their different grades and/or their different options, theymay have different functions installed therein and/or may have differentnumbers of functions installed therein.

SUMMARY OF THE INVENTION

In view of the background, an object of an aspect of the presentinvention is to allow diagnosis monitoring of a target function eventhough an operator to perform vehicle diagnosis monitoring cannot graspin advance which functions are installed in which control units.

According to one aspect of the present invention, there is provided avehicle communication system in which a plurality of control units arecommunicably linked to a communication network, and a monitoring deviceis designed to communicably linkable to the communication network and toestablish communications with at least one of the plurality of controlunits for monitoring. The vehicle communication system includes a firstidentifier uniquely assigned to at least one function for vehiclecontrol, The at least one function is installed in at least one of theplurality of control units. The vehicle communication system alsoincludes an identifying unit configured to identify that a targetfunction uniquely assigned with a target identifier is installed inwhich of the control units based on the first identifier and the targetidentifier.

According to another aspect of the present invention, there is providedan electronic control unit installed in a vehicle and designed tocontrol the vehicle. The control unit is communicably linked to acommunication network installed in the vehicle and communicably linkablethrough the communication network to a monitoring device designed toestablish communications with at least one of the plurality of controlunits for monitoring. The electronic control unit includes at least onefunction for vehicle control uniquely assigned with an identifier andinstalled therein. The electronic control unit also includes a receivingunit configured to receive a request message sent from the monitoringdevice. The request message contains the identifier of a target functionand descriptions used to monitor the target function. The electroniccontrol unit includes a determining unit configured to determine whetherthe target function whose identifier is contained in the request messageis installed therein. The electronic control unit includes an executingunit configured to execute the target function based on the descriptionscorresponding thereto when it is determined that the target functionwhose identifier is contained in the request message is installedtherein.

According to another aspect of the present invention, there is provideda system including a monitoring unit and a plurality of executing unitsin at least one of which a plurality of functions to be executed therebyare installed. The plurality of executing units are communicably linkedto a communication network. The monitoring device is designed toestablish communications with the plurality of executing units formonitoring. The system includes a first identifier uniquely assigned toeach of the plurality of functions, and a second identifier uniquelyassigned to each of the plurality of control units. The system alsoincludes an identifying unit configured to identify that a targetfunction uniquely assigned with a target identifier is installed inwhich of the control units based on a relationship between the firstidentifier, the second identifier, and the target identifier.

According to a further aspect of the present invention, there isprovided a vehicle communication method between a plurality of controlunits and a monitoring device. The plurality of control units arecommunicably linked to a communication network, The monitoring device isdesigned to communicably linkable to the communication network and toestablish communications with at least one of the plurality of controlunits for monitoring. The vehicle communication method includesproviding a first identifier uniquely assigned to at least one functionfor vehicle control, the at least one function being installed in atleast one of the plurality of control units; and identifying that atarget function uniquely assigned with a target identifier is installedin which of the control units based on the first identifier and thetarget identifier.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and aspects of the invention will become apparent from thefollowing description of embodiments with reference to the accompanyingdrawings in which:

FIG. 1 is a block diagram schematically illustrating an example of theconfiguration of a vehicle communication system according to a firstembodiment of the present invention;

FIG. 2 is a flowchart schematically illustrating an access controlprocessing to be executed by an external tool illustrated in FIG. 1;

FIG. 3 is a view schematically illustrating an example of theconfiguration of a data table according to the first embodiment;

FIG. 4 is a sequence diagram schematically illustrating the sequence ofactions to be executed by the external tool and each ECU and ofcommunications sent therebetween according to a second embodiment of thepresent invention;

FIG. 5 is a sequence diagram schematically illustrating the sequence ofactions to be executed by the external tool and each ECU and ofcommunications sent therebetween according to a third embodiment of thepresent invention;

FIG. 6 is a block diagram schematically illustrating an example of theconfiguration of a vehicle communication system according to a fourthembodiment of the present invention;

FIG. 7A is a flowchart schematically illustrating operations to beexecuted by a non-gate way ECU illustrated in FIG. 6;

FIG. 7B is a flowchart schematically illustrating operations to beexecuted by a gate way ECU illustrated in FIG. 6;

FIG. 7C is a flowchart schematically illustrating operations to beexecuted by a gate way ECU higher in level than that the gateway ECUassociated with the operations illustrated in FIG. 7B;

FIG. 7D is a flowchart schematically illustrating operations to beexecuted by gate way ECUs according to the fourth embodiment;

FIG. 8 is a block diagram schematically illustrating an example of theconfiguration of a vehicle communication system according to a fifthembodiment of the present invention;

FIG. 9A is a flowchart schematically illustrating operations to beexecuted by a non-gate way ECU illustrated in FIG. 8;

FIG. 9B is a flowchart schematically illustrating operations to beexecuted by a gate way ECU illustrated in FIG. 8;

FIG. 9C is a flowchart schematically illustrating operations to beexecuted by a gate way ECU higher in level than that the gateway ECUassociated with the operations illustrated in FIG. 9B;

FIG. 9D is a flowchart schematically illustrating operations to beexecuted by the gate way ECU higher in level than that the gateway ECUassociated with the operations illustrated in FIG. 9B;

FIG. 10 is a block diagram schematically illustrating an example of theconfiguration of a vehicle communication system according to a sixthembodiment of the present invention;

FIG. 11 is a sequence diagram schematically illustrating the sequence ofactions to be executed by the external tool and each ECU and ofcommunications sent therebetween according to a seventh embodiment ofthe present invention; and

FIG. 12 is a sequence diagram schematically illustrating the sequence ofactions to be executed by the external tool and each ECU and ofcommunications sent therebetween according to an eighth embodiment ofthe present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Embodiments of the present invention will be described hereinafter withreference to the accompanying drawings. In each embodiment, a vehiclecommunication system to which the present invention is applied will bedescribed hereinafter. Note that, in each embodiment, a plurality ofelectronic control units installed in a vehicle (target vehicle) will bereferred to as “ECUs”, and a diagnosis monitoring device disposedoutside of the vehicle will be referred to as “an external tool”.

First Embodiment

Referring to FIG. 1, a vehicle communication system S installed in thetarget vehicle according to a first embodiment of the present inventionincludes a number of, such as eight, ECUs 1 to 7 and 10. In addition,the vehicle communication system S includes an in-vehicle communicationnetwork 50 that allows the ECUs 1 to 7 and 10 to communicate with eachother. The communication network 50 is designed such that an externaltool 63 is removably linked thereto via a connector 61. The externaltool 63 is operative to establish a connection to each ECU via thecommunication network 50 and to communicate with each ECU for diagnosismonitoring.

Specifically, the communication network 50 according to the firstembodiment is composed of a first communication bus 51 and a secondcommunication bus 52 whose level is lower by one level than that of thefirst communication bus 51. For example, the first communication bus 51has the highest level in the communication network 50. The first andsecond communication buses 51 and 52 are linked to each other through agateway (G/W) to form a two-level hierarchical structure.

The five ECUs 1 to 5 and the ECU 10 are communicably coupled to thesecond communication bus 52, and the two ECUs 6 and 7 and the ECU 10 arecommunicably coupled to the first communication bus 51. The ECU 10serves as the gateway operative to interconnect the first and secondcommunication buses 51 and 52 and to route communication data (messages)therebetween. In the first embodiment, the ECU 10 is for exampledesigned specially for gateway.

Note that, in the specification, a message is a unit of data to be sentbetween a plurality of computing units, such as the ECUs and theexternal tool 63.

In the first embodiment, each of the ECUs is preferably composed of acomputer unit composed of at least a CPU, a memory installed withprograms causing the CPU to execute tasks, a communication interface,and an input/output (I/O) interface. The communication interface allowsthe CPU to communicate with another ECU linked to the communicationnetwork 50 therethrough. The input/output (I/O) interface allows the CPUto perform control operations associated with a target device installedin the vehicle.

A plurality of functions for vehicle control, such as engine controlfunction and air-conditioner control function are installed in advancein at least some of the ECUs (e.g. the memories thereof. The pluralityof functions can be installed in at least some of the ECUs in variousdata formats, such as program file formats.

The at least some of the ECUs are programmed to perform thecorresponding functions installed therein to control the vehicle.

A unique identifier has been statically set to each function sincevehicle development time; this unique identifier, referred to as FIDhereinafter, is indicative of each corresponding function.

Similarly, a unique identifier has been statically set to each ECU sincethe vehicle development time; this unique identifier, referred to as UIDhereinafter, is indicative of each corresponding ECU.

In the first embodiment, as illustrated in FIG. 1, as the UIDs, IDnumbers identical to the corresponding reference numerals assigned tothe ECUs 1 to 7 and 10 have been set thereto. For example, an ID number01 has been set as its UID to the ECU 1, and an ID number 10 has beenset as its UID to the ECU 10.

In the first embodiment, a first function (XX control function) assignedwith an FID equal to 01 is installed beforehand in each of the ECUs 1and 2. Similarly, a second function PXX diagnosis function) to which anFID equal to 02 has been assigned is installed beforehand in each of theECUs 1 to 3.

In addition, a third function (YY function) assigned with an FID equalto 03 is installed beforehand in the ECU 4. A fourth function (ZZcontrol function) to which an FID equal to 04 has been assigned isinstalled in advance in the ECU 5. A fifth function (VV system function)assigned with an FID equal to 05 is installed beforehand in each of theECUs 6 and 7.

As illustrated in FIG. 1, the external tool 63 is composed of a CPU 63a, a communication interface (I/F) 63 b, an internal memory 63 c, a cardinterface (I/F) 63 d, and an input and display unit 63 e. For example,the elements 63 a to 63 e of the external tool 63 operate by an internalbattery (not shown).

The CPU 63 a is electrically connected to the elements 63 b to 63 e. TheCPU 63 a is operative to communicate various types of items of data witheach of the elements 63 b to 63 e and to perform operations based on theitems of data.

The communication I/F 63 b is designed to be connected to the connector61, which establishes electrical connection between the communicationnetwork 50 and the CPU 63 a through the connector 61.

The internal memory 63 c includes, for example, a read only memory(ROM), a random access memory (RAM), or a flash memory in whichcommunication programs and data used upon execution of them are storedin advance. Especially, in the first embodiment, at least one of thecommunication programs causes the CPU 63 a to execute access controlprocessing using the data; this access control processing will bedescribed hereinafter (see FIG. 2 hereinafter).

The card I/F 63 d allows a memory card 65 to removably plug thereinto.The memory card 65 uses a rewritable memory, such as a nonvolatilememory, to store data that can be accessible and rewritable by the CPU63 a.

Note that, as the memory card 65, other types of removably memories canbe used. For example, disc memories or USB removable memories can beused in place of the memory card 65.

The input and display unit 63 e has a display for displaying data sentfrom the CPU 63 a in a visible format, and has a keyboard or a dataentry screen on the display; this keyboard or data entry screen allowsan operator to enter data into the CPU 63 a.

As illustrated in FIG. 3, the memory card 65 stores in advance a datatable T in which the relationship between the FIDs of the first to fifthfunctions and the UIDs of the ECUs 1 to 7 and 10 are recorded inadvance. The data table will be referred to as “FID-UID table”hereinafter.

Specifically, the FID-UID table T can represent that each function isinstalled in advance in what UID of ECUs. More simply, the FID-UID tableT can represent which functions are installed in advance in which of theECUs.

Note that such a FID-UID table T has been provided for individualvehicles that include different combinations of the functions and theECUs, and the FID-UID tables provided for the individual vehicles arestored in advance in different memory cards 65.

In addition, each of the ECUs of the vehicle communication system Soperates on power supplied from a power supply system PS installed inthe vehicle.

In the first embodiment and the other embodiments described hereinafter,the power supply system preferably starts to supply power to each of theECUs in response to an activate signal being input thereto.

For example, as the activate signal, an ignition switch signal can beused. The ignition switch signal represents the timing when an ignitionswitch IS of the vehicle is turned on by, for example, the location ofan ignition key of the vehicle being inserted in a key cylinder thereofto the ignition position from the off position by the vehicle's driver.

In addition, as the activate signal, a key switch signal can be used.The key switch signal represents the timing when a key switch KS isturned on in response to insertion of the ignition key into the keycylinder by the driver.

Next, the access control processing to be executed by the CPU 63 a ofthe external tool 63 upon access thereof to each of the ECUs 1 to 7 and10 linked to the communication network 50 will be described hereinafterwith reference to a flowchart illustrated in FIG. 2.

At first, an operator to perform vehicle diagnosis monitoring selectsany one of the memory cards 65 provided for individual vehicles; thisselected memory card 65 corresponds to the target vehicle in which thevehicle communication system S is installed in advance. Next, theoperator installs the selected memory card 65 into the external tool 63such that the memory card 65 plugs into the card I/F 63 d, which allowsthe CPU 63 a to access the memory card 65.

Subsequently, the operator manipulates the keyboard or the data entryscreen of the input and display unit 63 e to enter an FID correspondingto at least one of the functions as a target for diagnosis monitoring.In addition to the FID entry, the operator manipulates the keyboard orthe data entry screen of the input and display unit 63 e to enterdescriptions that are to instruct a corresponding ECU on what theoperator wants to monitor and diagnose regarding the target function.

Upon entry of the FID and the descriptions of the diagnosis monitoring,the CPU 63 a starts to execute the access control processing illustratedin FIG. 2. Upon entry of the descriptions of the diagnosis monitoring,the CPU 63 a can automatically determine an FID of at least one functionthat meets the entered descriptions.

As illustrated in FIG. 2, when starting the access control processing,the CPU 63 a accesses the memory card 65 to read the FID-UID table Ttherefrom, and searches the read FID-UID table T for UIDs correspondingto the entered FID of the target function in step S110.

Next, the CPU 63 a determines whether the UIDs corresponding to theentered FID have been retrieved in step S110 based on the searchedresult in step S120.

If it is determined that there are no UIDs in the read FID-UID table T(the determination in step S120 is NO), the CPU 63 a exits the accesscontrol processing.

Otherwise if it is determined that the UIDs corresponding to the enteredFID have been retrieved in step S110 (the determination in step S120 isYES), the CPU 63 a proceeds to step S130. In step S130, the CPU 63 acreates a list of the retrieved UIDs.

Next, in step S140, the CPU 63 a creates a request message identifying,as its destination, one ECU shown in the created list and requesting itto execute fault diagnosis in accordance with the entered descriptions,thereby sending the created request message to the communication network50. Thereafter, in step S140, the CPU 63 a deletes the UID correspondingto the ECU identified as the destination of the request message from thelist.

Note that messages to be communicated between the external tool 63 andthe ECUs or between one ECU and another include at least a data fieldand a header field preceding it. To the header field of the message,destination thereof is normally arranged.

In case of such a request message, the UID itself corresponding to theECU identified as the destination can be arranged to the header field,or another data indicative of an ECU identified as the destination canalso be arranged to the header field.

In the latter case, it is preferably to convert the UID indicative of anECU identified as the destination into destination data, and to arrangethe converted destination data to the header field of the requestmessage.

In addition, note that the request messages for diagnosis monitoringinclude a data acquisition request message that requests an ECUidentified as its destination to execute a function of:

acquiring control data that has been stored therein and specified in thedescriptions of the data acquisition request message; and

returning the acquired control data to the external tool 63.

The request messages for diagnosis monitoring also include an actuatordrive request message that requests an ECU identified as its destinationto execute a function of forcibly driving an actuator that is a controltarget of the ECU and has been specified in the descriptions in dataacquisition request message.

In step S150, the CPU 63 a determines whether there is another UID inthe list.

If it is determined there are no UIDs in the list (the determination instep S150 is NO), the CPU 63 a exits the access control processing.

Otherwise if it is determined that there is at least one UID in the list(the determination in step S150 is YES), the CPU 63 a returns to stepS140 and repeatedly performs the tasks in steps S140 and S150 unless thedetermination in step S150 is YES.

As described above, in the access control processing illustrated in FIG.2, the CPU 63 a of the external tool 63 is programmed to:

search the read FID-UID table T for UIDs corresponding to the enteredFID of the target function (see step S110); and

send the request message to each of the ECUs that correspond to theretrieved UIDs, respectively (see steps S120 to S150).

Specifically, according to the first embodiment, even if an operator toperform diagnosis monitoring of the target vehicle has no grasp wherethe target function is installed in the ECUs, the task in step S110 bythe CPU 63 a allows automatic identification of at least one ECU inwhich the target function is installed in advance. The tasks in stepsS130 to 150 therefore permit the request message for diagnosismonitoring to be sent to all of the identified ECUs.

This makes it possible for the operator to perform diagnosis monitoringof the target function without grasping which functions are installed inadvance in which of the ECUs.

In addition, each of the memory cards 65 store in advance a FID-UIDtable; these FID-UID tables have been provided for individual vehiclesincluding respectively different combinations of the functions and theECUs.

For this reason, replacement of one memory card 65 to be attached to theexternal tool 63 with a new memory card 65 can support for differentvehicles having different models, different grads and/or differentoptions.

Second Embodiment

A vehicle communication system according to a second embodiment of thepresent invention will be described hereinafter. As compared to thestructure of the vehicle communication system S according to the firstembodiment, the vehicle communication system according to the secondembodiment is specially configured such that the external tool 63automatically generates the FID-UID table T based on items ofinformation sent from each ECU. For this reason, the memory card 65 neednot necessarily be removable from the external tool 63.

Each of the ECUs 1 to 7 and 10 stores therein beforehand thecorresponding UID and the FID of corresponding at least one of thefunctions installed therein.

Except for the different points set forth above, the vehiclecommunication system of the second embodiment has substantially the samestructure as that of the vehicle communication system of the firstembodiment. For this reason, like reference characters are assigned tolike parts in the vehicle communication systems according to the firstand second embodiments so that descriptions of the parts of the vehiclecommunication system of the second embodiment will be omitted.

Next, operations of the vehicle communication system according to thesecond embodiment will be described hereinafter with reference to FIG.4. FIG. 4 is a sequence diagram schematically illustrating the sequenceof actions to be executed by the external tool 63 and each ECU and ofcommunications sent therebetween. In the second embodiment, the actionsand the communications are required to perform diagnosis monitoringprocessing according to the second embodiment.

While electrical connection between the communication network 50 and theexternal tool 63 is established, the CPU 63 a of the external tool 63initiates the diagnosis monitoring processing at power-up or at throwingof its activation switch, thereby broadcasting, to all of the ECUs, arequest message to check whether an ECU is communicable (see (1) in FIG.4). The request message to check whether an ECU is communicable will bereferred to as “communication check request message” hereinafter.

The communication check request message is a message with its headerfield to which destination information is arranged; this destinationinformation represents all of the ECUs as the destination for thecorresponding message. In other words, the destination informationrepresents an indefinite number of the ECUs as the destination for thecorresponding message. That is, the communication check request messageis a message to be broadcasted on the communication network 50.

When receiving the communication check request message, at least one ECUcommunicable with the external tool 63 and linked to the communicationnetwork 50 returns a communication acknowledge message containing itsown UID to the external tool 63 (see (2) in FIG. 4).

The CPU 63 a of the external tool 63 determines whether to receivecommunication acknowledge messages within a predetermined period afterbroadcasting the communication check request message (see (3) in FIG.4). In other words, the CPU 63 a determines whether communicationacknowledge messages have been sent from the ECUs.

If it is determined that no communication acknowledge messages have beenreceived within the predetermined period, the CPU 63 a for example exitsthe diagnosis monitoring processing.

Otherwise if it is determined that a communication acknowledge messagehave been received from, for example, each ECU within the predeterminedperiod, the CPU 63 a stores in, for example, the memory card 65 as acommunicable ECU. Specifically, the CPU 63 a stores in the internalmemory 63 c UIDs contained in the communication acknowledge messagesreturned from the ECUs as UIDs of communicable ECUs, respectively (see(3) in FIG. 4).

After checking of the communicable ECUs, an operator manipulates thekeyboard or the data entry screen of the input and display unit 63 e ofthe external tool 63 to enter an FID corresponding to at least one ofthe functions as a target for diagnosis monitoring. In addition to theFID entry, the operator manipulates the keyboard or the data entryscreen of the input and display unit 63 e to enter descriptions that areto instruct a corresponding ECU on what the operator wants to monitorand diagnose regarding the target function.

Upon entry of the FID and the descriptions of the diagnosis monitoring,the CPU 63 a of the external tool 63 creates a function check requestmessage inquiring, to each of the ECUs corresponding to the UIDs storedin the memory card 65 by the action (3) in FIG. 4, which functions areinstalled therein (see (4) in FIG. 4).

When receiving the function check request message, each of the ECUscorresponding to the UIDs stored in the memory card 65 by the action (3)in FIG. 4 creates a function acknowledge message that contains its ownUID and at least one FID corresponding to at least one functioninstalled therein. Thereafter, each of the ECUs sends the createdfunction acknowledge message to the external tool 63 (see (5) in FIG.4).

For example, because the ECU 4 has installed the third function (YNfunction) assigned with the FID 03, the function acknowledge messagethat contains its own UID (04) and the FID (03) corresponding to thethird function installed therein is sent from the ECU 4 to the externaltool 63 (see (5) in FIG. 4).

Similarly, because the ECU 2 has installed the first and secondfunctions (XX control function and XX diagnosis function) respectivelyassigned with the FIDs 01 and 02, the function acknowledge message thatcontains its own UID (02) and the FIDs (01 and 02) corresponding to thefirst and second functions installed therein is sent from the ECU 2 tothe external tool 63 (see (5) in FIG. 4).

The CPU 63 a of the external tool 63 receives the function acknowledgemessages sent from the communicable ECUs, creates an FID-UID table Tillustrated in, for example, FIG. 3 based on the received functionacknowledge messages, and thereafter, stores the created FID-UID table Tin the internal memory 63 c (see (6) in FIG. 4).

As well as the first embodiment, the FID-UID table T is designed torepresent each function is installed in advance in what UID of thecommunicable ECUs. More simply, the FID-UID table T is designed torepresent which functions are installed in advance in which communicableECUs.

The CPU 63 a of the external tool 63 reads the FID-UID table T from theinternal memory 63 c, and searches the read FID-UID table T for UIDscorresponding to the entered FID of the target function, which issimilar to step S110 (see (7) in FIG. 4).

Thereafter, the CPU 63 a of the external tool 63 executes the same tasksin step S120 to S150 in FIG. 2, thereby sending the request message tothe ECUs corresponding to the UIDs retrieved in the action (7) in FIG.4; this request message requests the ECUs to execute fault diagnosis inaccordance with the entered descriptions that are to instruct the ECUson what the operator wants to monitor and diagnose regarding the targetfunction.

Note that, in the second embodiment, as the request message sent fromthe external tool 63 to the ECU 4 by the action (8) in FIG. 4, a driverequest message that requests the ECU 4 to execute a function offorcibly driving an actuator that is a control target of the ECU 4 isillustrated by an example.

Specifically, upon receipt of the drive request message, the ECU 4executes a function (target function) of forcibly driving the actuator;this function is identified by the drive request message, which causesthe actuator to put in-vehicle devices into automatic action, such asforce or motion (see (9) in FIG. 4). The operator therefore can monitorand diagnose the operating state of each of the in-vehicle devices todetermine whether the target function (actuator driving function) isnormal or abnormal based on the monitored and diagnosed result.

As set forth above, the vehicle communication system according to thesecond embodiment can obtain the following effects in addition toallowing the operator to perform diagnosis monitoring of the targetfunction without grasping which functions are installed in advance inwhich of the ECUs. That is, it is unnecessary to install beforehand anFID-UID table in the external tool 63 and to provide FID-UID tables forindividual vehicles including respectively different combinations of thefunctions and the ECUs.

Specifically, it is possible to eliminate the necessity to manuallymanage FID-UID tables, thereby improving the enhance of operators indiagnosis monitoring of the functions installed in the ECUs linked tothe communication network 50.

In addition, the actions (1) to (3) in FIG. 4 allow the external tool 63not to send the function acknowledge message to ECUs that are difficultto communicate with the external tool 63, making it possible to reducethe communication load on the communication network 50.

Note that the actions (1) to (3) in FIG. 4 can be executed after theoperator enters a communication check instruction to the CPU 63 a of theexternal tool 63 by manipulating the input and display unit 63 e. Inaddition, note that the actions (1) to (3) in FIG. 4 can be carried out,before sending of the function check request message, in response toentry of an FID corresponding to at least one of the functions as atarget for diagnosis monitoring and descriptions representing what theoperator wants to monitor and diagnose regarding the target function.

Third Embodiment

A vehicle communication system according to a third embodiment of thepresent invention will be described hereinafter. As compared to thestructure of the vehicle communication system according to each of thefirst and second embodiments, the vehicle communication system accordingto the third embodiment is specially configured such that the externaltool 63 identifies at least one ECU in which a target function isinstalled without using an FID-UID table. In the FID-UID table, therelationship between the FIDs of all of functions and the UIDs of all ofthe ECUs are recorded in advance.

Specifically, the vehicle communication system according to the thirdembodiment is specially configured such that the external tool 63identifies at least one ECU to which the request message should be sentwithout using the FID-UID table.

As with the second embodiment, each of the ECUs 1 to 7 and 10 storestherein beforehand the corresponding UID and the FID of corresponding atleast one of the functions installed therein.

Except for the different points set forth above, the vehiclecommunication system of the third embodiment has substantially the samestructure as that of the vehicle communication system of the firstembodiment. For this reason, like reference characters are assigned tolike parts in the vehicle communication systems according to the firstand third embodiments so that descriptions of the parts of the vehiclecommunication system of the third embodiment will be omitted.

Next, operations of the vehicle communication system according to thethird embodiment will be described hereinafter with reference to FIG. 5.FIG. 5 is a sequence diagram schematically illustrating the sequence ofactions to be executed by the external tool 63 and each ECU and ofcommunications sent therebetween. In the third embodiment, the actionsand the communications are required to perform diagnosis monitoringprocessing according to the third embodiment.

While electrical connection between the communication network 50 and theexternal tool 63 through the connector 61 is established, an operatormanipulates the keyboard or the data entry screen of the input anddisplay unit 63 e of the external tool 63 to enter an FID correspondingto at least one of the functions as a target for diagnosis monitoring.

In addition to the FID entry, the operator manipulates the keyboard orthe data entry screen of the input and display unit 63 e to enterdescriptions that are to instruct a corresponding ECU on what theoperator wants to monitor and diagnose regarding the target function.

Upon entry of the FID and the descriptions of the diagnosis monitoring,the CPU 63 a of the external tool 63 creates a function inquiry messagecontaining the FID corresponding to the target function and inquiring,to all of the ECUs linked to the communication network 50, whether thetarget function is installed therein. Then, the CPU 63 a sends thecreated function inquiry message to all of the ECUs (see (1) in FIG. 5).

When receiving the function inquiry message, each of the ECUs determineswhether the function corresponding to the FID contained in the functioninquiry message is installed therein (see (2) in FIG. 5).

In the third embodiment, for example, the function inquiry messagecontaining the FID (01) corresponding to the first function (targetfunction) is sent from the external tool 63 to all of the ECUs 1 to 7and 10.

Because each of the ECUs 1 and 2 has installed the first functioncorresponding to the FID (01), each of the ECUs 1 and 2 creates afunction inquiry response message containing its own UID, therebysending it to the external tool 63 (see (3) in FIG. 5).

In contrast, because the remaining ECUs 3 to 7 and 10 have not installedthe first function corresponding to the FID (01), the remaining ECUs 3to 7 and 10 send no function inquiry response message to the externaltool 63 (see (3A) in FIG. 5).

The CPU 63 a of the external tool 63 receives the function inquiryresponse messages sent from the ECUs 1 and 2, and creates a list of theUIDs contained respectively in the received function inquiry responsemessages, which is the same task as that in step S130 of FIG. 2 (see (4)in FIG. 5). Specifically, the created list recites at least one ECU inwhich the target function is installed.

Then, the CPU 63 a of the external tool 63 executes the same tasks instep S140 and S150 in FIG. 2, and thereafter sends the request messageto the ECUs corresponding to the UIDs recited in the list created by theaction (4) in FIG. 5 (see (5) and (7) in FIG. 5). The request messagesent from the CPU 63 a requests the ECUs to execute fault diagnosis inaccordance with the entered descriptions that are to instruct the ECUson what the operator wants to monitor and diagnose regarding the targetfunction.

Note that, in the third embodiment, as the request message sent from theexternal tool 63 by the action (5) in FIG. 5, a data acquisition requestmessage is illustrated by an example. The data acquisition requestmessage requests an ECU identified as its destination to execute afunction of acquiring control data that has been stored therein andspecified in the descriptions of the data acquisition request message,and returning the acquired control data to the external tool 63.

Specifically, as illustrated by the action (5) in FIG. 5, when the dataacquisition request message is sent from the external tool 63 to, forexample, the ECU 2, the ECU 2 executes a data acquisition function (thetarget function) of:

acquiring control data that has been stored therein and specified in thedescriptions of the data acquisition request message;

creating, as the function inquiry response message, a data acquisitionresponse message with the data field to which the acquired control datais arranged; and

returning the created data acquisition response message to the externaltool 63 (see (6) in FIG. 5).

Moreover, as illustrated by the action (7) in FIG. 5, when the dataacquisition request message is sent from the external tool 63 to, forexample, the ECU 1, the ECU 1 executes a data acquisition function (thetarget function) of:

acquiring control data that has been stored therein and specified in thedescriptions of the data acquisition request message;

creating, as the function inquiry response message, a data acquisitionresponse message with the data field to which the acquired control datais arranged; and

returning the created data acquisition response message to the externaltool 63.

The CPU 63 a of the external tool 63 receives the data acquisitionresponse messages sent from the ECUs 1 and 2, and displays, on the inputand display unit 63 e, the items of control data contained in thereceived data acquisition response messages in a visible format (see (9)in FIG. 5).

The operator therefore can monitor and diagnose contents and/or valuesof the items of control data displayed on the input and display unit 63e to determine whether the target function (data acquisition function)is normal or abnormal based on the monitored and diagnosed result.

Specifically, the external tool 63 according to the third embodiment isconfigured to:

send, to all of the ECUs, the function inquiry request messagecontaining an FID corresponding to a target function; and

identify that at least one ECU corresponding to an UID contained in thefunction inquiry response message sent from at least one ECU is an ECUin which the target function is installed.

As set forth above, in the vehicle communication system according to thethird embodiment, in addition to the effects obtained by the secondembodiment, it is unnecessary for the external tool 63 to create andhold an FID-UID table in which the relationship between the FIDs of allof the functions and the UIDs of all of the ECUs are recorded inadvance. This makes it possible to reduce the processing load requiredto create the FID-UID table and the storage capacity in the internalmemory 63 c required to store the FID-UID table.

Fourth Embodiment

A vehicle communication system SA according to a fourth embodiment ofthe present invention will be described hereinafter. As compared to thestructure of the vehicle communication system according to the firstembodiment, the external tool 63 and the ECUs of the vehiclecommunication system according to the fourth embodiment are similarlyconfigured to execute the actions illustrated by (1) to (8) in FIG. 5.

Specially, in the fourth embodiment, a communication network 50A isdesigned to form a three-level hierarchical structure. In addition, inthe fourth embodiment, the vehicle communication system SA includes anumber of, such as twelve ECUs 1 to 8, 10, 20, 30, and 40. Each of theECUs 1 to 8, 10, 20, 30, and 40 is operative to additionally execute thetasks (A) to (D) described hereinafter.

As illustrated in FIG. 6, the communication network 50A is composed of afirst communication bus 51A, a pair of second communication buses 52Aand 53A whose levels are lower by one level than that of the firstcommunication bus 51A, and a pair of third communication buses 54A and55A whose levels are lower by one level than those of the secondcommunication buses 52A and 53A.

The first communication bus 51A is configured to be communicablylinkable to an external tool 63A via a connector 61.

The ECUs 1, 2, 10, and 20 are communicably coupled to the firstcommunication bus 51A, the ECUs 3, 10, and 30 are communicably coupledto the second communication bus 52A, and the ECUs 6, 20, and 40 arecommunicably coupled to the second communication bus 53A. The ECUs 4, 5,and 30 are communicably coupled to the third communication bus 54A, andthe ECUs 7, 8, and 40 are communicably coupled to the thirdcommunication bus 55A.

Specifically, the first communication bus 51A and the secondcommunication bus 52A are linked to each other through the ECU 10 thatserves as a gateway operative to interconnect the first and secondcommunication buses 51A and 52A and to route communication data(messages) therebetween.

The first communication bus 51A and the second communication bus 53A arelinked to each other through the ECU 20 that serves as a gatewayoperative to interconnect the first and second communication buses 51Aand 53A and to route communication data (messages) therebetween.

The second communication bus 52A and the third communication bus 54A arelinked to each other through the ECU 30 that serves as a gatewayoperative to interconnect the second and third communication buses 52Aand 54A and to route communication data (messages) therebetween.

The second communication bus 53A and the third communication bus 55A arelinked to each other through the ECU 40 that serves as a gatewayoperative to interconnect the second and third communication buses 53Aand 55A and to route communication data (messages) therebetween.

In the fourth embodiment, each of the ECUs 20 and 30 is for exampledesigned specially for gateway, but the ECUs 10 and 40 are alsooperative to execute vehicle control like each of the ECUs 1 to 8. Notethat, in case of distinguishing between the ECUs 10, 20, 30, and 40 andthe ECUs 1 to 8, the ECUs 10, 20, 30, and 40 serving as a gateway willbe collectively referred to gateway ECUs, and the remaining ECUs 1 to 8will be collectively referred to as non-gateway ECUs hereinafter.

In the fourth embodiment, as well as the first to third embodiments, asunique identifiers (UIDs), ID numbers identical to the correspondingreference numerals assigned to the ECUs 1 to 8, 10, 20, 30, and 40 havebeen set thereto. For example, an ID number 01 has been set as its UIDto the ECU 1, an ID number 10 has been set as its UID to the ECU 10, andan ID number 30 has been set as its UID to the ECU 30.

In the fourth embodiment, a first function assigned with an FID equal to01 is installed beforehand in each of the ECUs 1, 5, 7, 10, 20, 30, and40, and a second function to which an FID equal to 02 has been assignedis installed beforehand in each of the ECUs 2, 4, 5, 10, and 30.Similarly, a third function assigned with an FID equal to 03 isinstalled beforehand in each of the ECUs 3 and 10, and a fourth functionassigned with an FID equal to 04 is installed beforehand in the ECU 4.

A sixth function to which an FID equal to 06 has been assigned isinstalled beforehand in each of the ECUs 6 and 20, and an eighthfunction assigned with an FID equal to 08 is installed beforehand ineach of the ECUs 8, 10, and 40. An eleventh function to which an FIDequal to 11 has been assigned is installed beforehand in the ECU 10, anda thirteenth function assigned with an FID equal to 13 is installedbeforehand in each of the ECUs 20 and 40.

Each of the ECUs 1 to 8, 10, 20, 30, and 40 stores therein beforehandthe corresponding UID and the FID of corresponding at least one of thefunctions installed therein.

Except for the different points set forth above, the vehiclecommunication system SA of the fourth embodiment has substantially thesame structure as that of the vehicle communication system of the firstembodiment. For this reason, like reference characters are assigned tolike parts in the vehicle communication systems according to the firstand fourth embodiments so that descriptions of the parts of the vehiclecommunication system of the fourth embodiment will be omitted.

Next, operations of the vehicle communication system SA according to thefourth embodiment will be described hereinafter with reference to FIGS.7A to 7D.

When a power supply from the power supply system PS is started to theECUs, each of the non-gateway ECUs 3 to 8 linked to the second and thirdcommunication buses 52A to 55A lower by one level than the firstcommunication bus 51A executes the task (A) in step S200 of FIG. 7A.

Specifically, in step S200, each non-gateway ECU informs one gateway ECUabout a message containing the FID of at least one function installedtherein; this gateway ECU is intermediate between the correspondingsecond or third communication bus linked to each non-gateway ECU andanother communication bus whose level is higher by one level than thatof the corresponding second or third communication bus.

For example, in step S200, the non-gateway ECU 5 informs the gateway ECU30 about a message containing the FIDs (01 and 02), and the non-gatewayECU 6 informs the gateway ECU 20 about a message containing the FID(06).

Note that, in the fourth embodiment and the other embodiments describedhereinafter, the power supply system PS starts to supply power to eachof the ECUs in response to an activate signal being input thereto.

For example, as the activate signal, an ignition switch signal can beused. The ignition switch signal represents the timing when an ignitionswitch of the vehicle is turned on by, for example, the location of anignition key of the vehicle being inserted in a key cylinder thereof tothe ignition position from the off position by the vehicle's driver.

In addition, as the activate signal, a key switch signal can be used.The key switch signal represents the timing when a key switch is turnedon in response to insertion of the ignition key into the key cylinder bythe driver.

When the power supply system PS starts to supply power to the ECUs inresponse to an activate signal, such as the ignition switch signal orthe key switch signal, being input thereto, each of the gateway ECUs 3.0and 40 except for the gateway ECUs 10 and 20 executes the task (B) insteps S300 to S320 of FIG. 7B.

In step S300, each of the gateway ECUs 30 and 40 receives the messagecontaining the FIDs informed from at least one of the gateway andnon-gateway ECUs linked to the corresponding third communication bus 54Aor 55A. The third communication bus 54A or 55A linked to each of thegateway ECUs 30 and 40 is lower by one level than the secondcommunication bus 52A or 53A linked thereto.

Next, in step S310, the gateway ECUs 30 and 40 create function lists L30and L40 in which the received FIDs are recorded, respectively.

Subsequently, the gateway ECUs 30 and 40 inform the higher gateway ECUs,such as ECUs 10 and 20, about a message containing the FIDs recorded inthe created lists L30 and L40, respectively; these higher gateway ECUsare higher by one level than the gateway ECUs 30 and 40, respectively instep S320.

In step S320, in addition to the FIDs recorded in the created lists L30and L40, the gateway ECUs 30 and 40 inform the higher gateway ECUs abouta message containing the FID at least one function installed therein.

Specifically, an FID informed from a non-gateway ECU to a gateway ECU isused to create a function list by the gateway ECU. In addition, an FIDinformed from a gateway ECU to another gateway ECU higher by one levelthan the gateway ECU is used to crease a function list by the highergateway ECU.

When the power supply system PS starts to supply power to the ECUs inresponse to an activate signal, such as an ignition switch signal or keyswitch signal, being input thereto, each of the gateway ECUs 10 and 20linked to the top-level communication bus 51A executes the task (C) insteps S400 and S410 of FIG. 7C.

In step S400, each of the gateway ECUs 10 and 20 receives the FIDsinformed from at least one of the gateway and non-gateway ECUs linked tothe corresponding second communication bus 52A or 53A. The secondcommunication bus 52A or 53A linked to each of the gateway ECUs 10 and20 is lower by one level than the first communication bus 51A linkedthereto.

Next, in step S410, the gateway ECUs 10 and 20 create function lists L10and L20 in which the received FIDs are recorded, respectively.

Moreover, when receiving the function inquiry message sent from theexternal tool 63, each of the gateway ECUs 10, 20, 30, and 40 executesthe task (D) in step S500 of FIG. 7D.

Specifically, each of the gateway ECUs 10, 20, 30, and 40 relays thereceived function inquiry message to the destination only when at leastone FID contained in the function inquiry message has been recorded inthe function list created thereby in step S500.

Note that, in the fourth embodiment, each of the gateway ECUs 10, 20,30, and 40 is configured to execute the actions (2) and (3) illustratedin FIG. 5 like each of the non-gateway ECUs 1 to 8. Specifically, eachof the ECUs 10, 20, 30, and 40 determines whether the functioncorresponding to at least one FID contained in the function inquirymessage is installed therein (see (2) in FIG. 5).

If it is determined that each of the ECUs 10, 20, 30, and 40 hasinstalled the function corresponding to at least one FID contained inthe function inquiry message, each of the ECUs 10, 20, 30, and 40creates a function inquiry response message containing its own UID.Then, each of the ECUs 10, 20, 30, and 40 sends the created functioninquiry response message to the external tool 63 (see (3) in FIG. 5).

Note that, in the fourth embodiment, messages to be sent to a gatewayECU from an ECU lower than the gateway ECU include at least a headerfield and a data field. To the header field of the message,identification information representing that this message is acommunication message used to create a function list is arranged. Theidentification information allows the gateway ECU to securely and simplydistinguish between messages used to create a function list and normalcommunication messages.

Next, the tasks (A) to (D) will be described with reference to FIGS. 6and 7A to 7D.

When the power supply system PS starts to feed power to the ECUs inresponse to, for example, turning on of the ignition switch IS of thevehicle, the non-gateway ECU 4 executes the task (A) (step S200) tonotify the gateway ECU 30 of the message containing the FID (02) of thesecond function installed therein. Similarly, the non-gateway ECU 5executes the task (A) to notify the gateway ECU 30 of the messagecontaining the FIDs (01 and 02) of the first and second functionsinstalled therein.

Upon the power supplied to the ECUs, the non-gateway ECU 3 notifies thegateway ECU 10 of the message containing the FID (03) of the thirdfunction installed therein. Similarly, the non-gateway ECUs 7 and 8notify the gateway ECU 40 of the messages containing the FID (01) andthe FID (08) of the first and eighth functions installed therein,respectively In response to start of power supply to the ECUs, thenon-gateway ECU 6 notifies the gateway ECU 20 of the message containingthe FID (06) of the sixth function installed therein.

The gateway ECU 30 executes the task (B) (steps S300 to S320) to;

receive the FIDs (01 and 02) informed from the ECUs 4 and 5 linked tothe lower communication bus 54A;

create the function list L30 in which the received FIDs (01 and 02) arerecorded; and

notify the higher gateway ECU 10 of the message containing the FIDs (01and 02) recorded in the function list L30 because the gateway ECU 30includes no functions associated with vehicle control.

The gateway ECU 40 executes the task (B) (steps S300 to S320) to:

receive the FIDs (01 and 08) informed from the ECUs 7 and 8 linked tothe lower communication bus 55A;

create the function list L40 in which the received FIDs (01 and 08) arerecorded; and

notify the higher gateway ECU 20 of the message containing the FIDs (01and 08) recorded in the function list L30 and the FID (13) of thethirteenth function contained therein.

The gateway ECU 10 executes the task (C) (steps S400 to S410) to:

receive the FIDs (01, 02, and 03) informed from the ECUs 3 and 30 linkedto the lower communication bus 52A; and

create the function list L10 in which the received FIDs (01, 02, and 03)are recorded.

The gateway ECU 20 executes the task (C) (steps S400 to S410) to:

receive the FIDs (01, 06, 08, and 13) informed from the ECUs 6 and 40linked to the lower communication bus 53A; and

create the function list L20 in which the received FIDs (01, 06, 08, and13) are recorded.

Thereafter, it is assumed that the CPU 63 a of the external tool 63executes the action (1) in FIG. 5 to send, to each of the ECUs linked tothe communication network 50A, the function inquiry message containingthe FID (02) of the second function as the target function (see thetwo-dot chain arrow Y1 in FIG. 6).

In this case, because the FID (02) is recorded beforehand in thefunction lists L10 and L30 created by the gateway ECUs 10 and 30, thegateway ECUs 10 and 30 execute the task (D) to receive the functioninquiry message, thereby relaying the function inquiry message to theECUs lower in level than the gateway ECUs 10 and 30 (see two-dot chainlines shown by the two-dot chain arrows Y2 and Y3 in FIG. 6).

In contrast, no FID (02) is recorded in each of the function lists L20and L40 created by the gateway ECUs 20 and 40. For this reason, each ofthe gateway ECUs 20 and 40 does not relay the function inquiry messageto the ECUs lower in level than each of the gateway ECUs 20 and 40.Specifically, in the fourth embodiment, when the external tool 63 sendsthe function inquiry message containing the FID (02), the functioninquiry message is not relayed to the second communication bus 53A andthe third communication bus 55A.

Based on the function inquiry message sent to the ECUs 2, 4, and 5, eachof the ECUs 2, 4, and 5 sends the function inquiry response messagecontaining its own UID.

As illustrated by the dashed arrow Y7, the function inquiry responsemessage sent from the ECU 2 is transferred via only the communicationbus 51A to be received by the external tool 63.

On the other hand, as illustrated by the dashed arrows Y4 to Y7, thefunction inquiry response messages sent from the ECUs 4 and 5 aretransferred via the communication bus 54A, the gateway ECU 30, thecommunication bus 52A, the gateway ECU 10, and the communication bus 51Ato be received by the external tool 63.

As set forth above, in the vehicle communication system SA according tothe fourth embodiment, in addition to the effects obtained by the thirdembodiment, the function inquiry message sent from the external tool 63can be prevented from being relayed to part of the communication network50A to which at least one ECU installed with no target functions is onlylinked. For example, in the case of the function inquiry message withthe FID (02), the function inquiry message can be prevented from beingrelayed to the second communication bus 53A and the third communicationbus 55A.

This makes it possible to reduce the communication load via thecommunication network 50A and the communication processing load of eachof the ECUs.

In addition, reduction of the communication load through thecommunication network 50A also can shorten a period from when theexternal tool 63 sends the function inquiry message until when itreceives the function inquiry response message corresponding to the sentfunction inquiry message. This makes it possible to reduce the time forthe external tool 63 to identify at least one ECU installed with thetarget function. More specifically, it is possible to reduce the timefor the external tool 63 to create the list by executing the action (4)in FIG. 5.

Fifth Embodiment

A vehicle communication system SB according to a fifth embodiment of thepresent invention will be described hereinafter with reference to FIGS.8 and 9A to 9D.

As compared to the structure of the vehicle communication system SAaccording to the fourth embodiment, the vehicle communication system SBof the fifth embodiment has substantially the same structure as that ofthe vehicle communication system SA of the fourth embodiment. For thisreason, like reference characters are assigned to like parts in thevehicle communication systems according to the fourth and fifthembodiments so that descriptions of the parts of the vehiclecommunication system of the fifth embodiment will be omitted.

In the fifth embodiment, each of the ECUs 1 to 8, 10, 20, 30, and 40 isoperative to execute the tasks (a) to (d) in place of the tasks (A) to(D):

When power supply system PS starts to supply power to the ECUs inresponse to an activate signal, such as an ignition switch signal or akey switch signal, being input thereto, each of the non-gateway ECUs 3to 8 linked to the second and third communication buses 52A to 55A lowerthan the first communication bus 51A executes the task (a) in step S600of FIG. 9A.

Specifically, in step S600, each non-gateway ECU informs one gateway ECUabout, as data table creating information, a message containing the FIDof at least one function installed therein and its own UID. The onegateway ECU is intermediate between the corresponding second or thirdcommunication bus linked to each non-gateway ECU and anothercommunication bus whose level is higher by one level than that of thecorresponding second or third communication bus.

For example, in step S600, the non-gateway ECU 5 informs the gateway ECU30 about a message containing the FIDs (01 and 02) and its own UID (05),and the non-gateway ECU 6 informs the gateway ECU 20 about a messagecontaining the FID (06) and its own UID (06).

When the power supply system PS starts to supply power to each of theECUs in response to an activate signal, such as an ignition switchsignal or a key switch signal being input thereto, each of the gatewayECUs 30 and 40 except for the gateway ECUs 10 and 20 executes the task(b) in steps S700 to S720 of FIG. 9B.

In step S700, each of the gateway ECUs 30 and 40 receives the data tablecreating information informed from at least one of the gateway andnon-gateway ECUs linked to the corresponding third communication bus 54Aor 55A. The third communication bus 54A or 55A linked to each of thegateway ECUs 30 and 40 is lower by one level than the secondcommunication bus 52A or 53A linked thereto.

Next, in step S710, the gateway ECUs 30 and 40 create FID-UID tables T30and T40 based on the received data table creating information,respectively. The FID-UID table T30 has recorded therein therelationship between:

the FID of at least one function installed in at least one of thegateway and non-gateway ECUs linked to the corresponding thirdcommunication bus 54A;

the FID of at least one function installed in the gateway ECU 30 whereit exists (in the fifth embodiment, no functions are installed in theECU 30); and

the UID of its own gateway ECU 30.

Similarly, the FID-UID table T40 has recorded therein the relationshipbetween:

the FID of at least one function installed in at least one of thegateway and non-gateway ECUs linked to the corresponding thirdcommunication bus 55A;

the FID of at least one function installed in the gateway ECU 40 whereit exists (in the fifth embodiment, the thirteen function with the FID(13) is installed in the ECU 40); and

the UID of its own gateway ECU 40.

Subsequently, in step S720, the gateway ECUs 30 and 40 inform the highergateway ECUs 10 and 20 about the created FID-UID tables T30 and T40 asdata table creating information, respectively.

When the power supply system PS starts to supply power from the powersupply system PS in response to an activate signal, such as an ignitionswitch signal or a key switch signal, each of the gateway ECUs 10 and 20linked to the top-level communication bus 51A executes the task (c) insteps S800 and S810 of FIG. 9C.

In step S800, each of the gateway ECUs 10 and 20 receives the data tablecreating information informed from at least one of the gateway andnon-gateway ECUs linked to the corresponding second communication bus52A or 53A. The second communication bus 52A or 53A linked to each ofthe gateway ECUs 10 and 20 is lower by one level than the firstcommunication bus 51A linked thereto.

Next, in step S810, the gateway ECUs 10 and 20 create FID-UID tables T10and T20 based on the received data table creating information,respectively. The FID-UID table T10 has recorded therein therelationship between:

the FID of at least one function installed in at least one of thegateway and non-gateway ECUs linked to the corresponding secondcommunication bus 52A;

the FID of at least one function installed in the gateway ECU10 where itexists (in the fifth embodiment, the eleventh function with the FID (13)is installed in the ECU 10); and

the UID of its own gateway ECU 10.

Similarly, the FID-UID table T20 has recorded therein the relationshipbetween:

the FID of at least one function installed in at least one of thegateway and non-gateway ECUs linked to the corresponding secondcommunication bus 53A;

the FID of at least one function installed in the gateway ECU 20 whereit exists (in the fifth embodiment, no functions are installed in theECU 20); and

the UID of its own gateway ECU 20.

Moreover, when receiving the function inquiry message sent from theexternal tool 63, each of the gateway ECUs 10 and 20 executes the task(d) in steps S900 and S930 of FIG. 9D.

Specifically, each of the gateway ECUs 10 and 20 determines whether atleast one FID contained in the received function inquiry message isstored in the FID-UID table created thereby in step S900.

If it is determined that at least one FID contained in the receivedfunction inquiry message is not stored in the FID-UID table created byeach of the ECUs 10 and 20 (the determination in step S900 is NO), nofunction inquiry response message is sent therefrom to the external tool63 in step S910, the task (D) is terminated.

Otherwise if it is determined that at least one FID contained in thereceived function inquiry message is stored in the FID-UID table createdby each of the ECUs 10 and 20 (the determination in step S900 is YES),each of the ECUs 10 and 20 goes to step S920. In step S920, each of theECUs 10 and 20 retrieves at least one UID stored in the correspondingFID-UID table to be associated with the at least one FID.

Then, each of the ECUs 10 and 20 sends a function inquiry responsemessage containing the retrieved at least one UID to the external tool63 in step S930.

Note that, in the fifth embodiment, messages to be sent, for use in thedata table creating information, to a gateway ECU from an ECU lower thanthe gateway ECU include at least a header field and a data field. To theheader field of the message, identification information representingthat this message is a communication message used to create an FID-UIDtable is arranged. The identification information allows the gateway ECUto securely and simply distinguish between messages used to create anFID-UID table and normal communication messages.

Next, the tasks (a) to (d) will be described with reference to FIGS. 8and 9A to 9D.

When the power supply system PS starts to feed power to the ECUs inresponse to turning on of, for example, the ignition switch IS of thevehicle, the non-gateway ECU 4 executes the task (a) (step S600).Specifically, the non-gateway ECU 4 notifies the gateway ECU 30 of themessage containing the FID (02) of the second function installed thereinand its own UID (04). Similarly, the non-gateway ECU 5 executes the task(a) to notify the gateway ECU 30 of the message containing the FIDs (01and 02) of the first and second functions installed therein and its ownUID (05).

Upon the power supplied to the ECUs, the non-gateway ECU 3 notifies thegateway ECU 10 of the message containing the FID (03) of the thirdfunction installed therein and its own UID (30). Similarly, thenon-gateway ECU 7 notifies the gateway ECU 40 of the message containingthe FID (01) of the first function installed therein and its own UID 07.In addition, the non-gateway ECU 8 notifies the gateway ECU 40 of themessage containing the FID (08) of the eighth function installed thereinand its own UID (08). In response to start of power supply to the ECUs,the non-gateway ECU 6 notifies the gateway ECU 20 of the messagecontaining the FID (06) of the sixth function installed therein and itsown UID (06).

The gateway ECU 30 executes the task (b) (steps S700 to S720) to:

receive the FIDs and the UIDs informed from the ECUs 4 and 5 linked tothe lower communication bus 54A;

create the FID-UID table T30 illustrated in FIG. 8 based on only thereceived FIDs and the UIDs because no functions are installed therein;and

notify the higher gateway ECU 10 of a message containing informationindicative of the contents of the FID-UID table T30.

Specifically, as illustrated in FIG. 8, in the table T30, the FID (01)is recorded to be associated with the UID (05) in which thecorresponding first function is installed, and the FID (02) is recordedto be associated with the UIDs (04 and 05) in which the correspondingsecond function is installed.

Similarly, the gateway ECU 40 executes the task (b) (steps S700 to S720)to:

receive the FIDs and the UIDs informed from the ECUs 7 and 8 linked tothe lower communication bus 55A;

create the FID-UID table T40 illustrated in FIG. 8 based on the receivedFIDs and the UIDs and the FID (13) of the thirteen function installedtherein; and

notify the higher gateway ECU 20 of a message containing informationindicative of the contents of the FID-UID table T40.

Specifically, as illustrated in FIG. 8, in the table T40, the FID (01)is recorded to be associated with the UID (07) in which thecorresponding first function is installed, and the FID (08) is recordedto be associated with the UID (08) in which the corresponding eighthfunction is installed. Similarly, in the table T40, the FID (13) isrecorded to be associated with the UID (40) in which the correspondingthirteenth function is installed.

The gateway ECU 10 executes the task (c) (steps S800 to S810) to:

receive the FIDs and UIDs informed from the ECUs 3 and 30 linked to thelower communication bus 52A; and

create the FID-UID table T10 based on the received FIDs and UIDs and theFID (11) of the eleventh function installed therein.

Specifically, as illustrated in FIG. 8, in the table T10, the FID (01)is recorded to be associated with the UID (05) in which thecorresponding first function is installed, and the FID (02) is recordedto be associated with the UIDs (04 and 05) in which the correspondingsecond function is installed. In addition, in the table T10, the FID(03) is recorded to be associated with the UID (03) in which thecorresponding third function is installed, and the FID (11) is recordedto be associated with the UID (10) in which the corresponding eleventhfunction is installed.

Similarly, the gateway ECU 20 executes the task (c) (steps S800 to S810)to:

receive the FIDs and UIDs informed from the ECUs 6 and 40 linked to thelower communication bus 53A; and

create the FID-UID table T20 based on only the received FIDs and UIDsbecause no functions are installed therein.

Specifically, as illustrated in FIG. 8, in the table T20, the FID (01)is recorded to be associated with the UID (07) in which thecorresponding first function is installed, and the FID (06) is recordedto be associated with the UID (06) in which the corresponding sixthfunction is installed. In addition, in the table T20, the FID (08) isrecorded to be associated with the UID (08) in which the correspondingeighth function is installed, and the FID (13) is recorded to beassociated with the UID (40) in which the corresponding thirteenthfunction is installed.

Thereafter, it is assumed that the CPU 63 a of the external tool 63executes the action (1) in FIG. 5 to send, to each of the ECUs linked tothe communication network 50A, the function inquiry message containingthe FID (02) of the second function as the target function (see two-dotchain lines shown by the two-dot chain arrow Y1 in FIG. 8).

In this case, because the FID (02) is recorded beforehand in the UID-FIDtable T10 created by the gateway ECU 10, the gateway ECU 10 executes thetask (d) to:

determine that the FID (02) is stored in the FID-UID table T10;

retrieve the UIDs (04 and 05) recorded in the FID-UID table T10 to beassociated with the FID (02); and

send a function inquiry response message containing the retrieved UIDs(04 and 05) to the external tool 63 (see dashed line shown by the dashedarrow Y10 in FIG. 8).

In contrast, because the FID (02) is not recorded beforehand in theUID-FID table T12 created by the gateway ECU 20, the gateway ECU 20executes the task (d) to send no function inquiry response message tothe external tool 63.

Note that, in the fifth embodiment, based on the function inquirymessage sent to the ECU 2, the ECU 2 linked to the first communicationbus 51A executes actions (2) and (3) in FIG. 5 to send the functioninquiry response message containing its own UID (02) to the externaltool 63.

In addition, in the fifth embodiment, because it is unnecessary torelay, to the communication buses lower in level than the firstcommunication bus 51A, function inquiry messages sent from the externaltool 63. This allows each of the gateway ECUs 10 and 20 not to relay thefunction inquiry messages sent from the external tool 63 to the secondcommunication bus 52A or 53A.

As illustrated in FIG. 8, therefore, when the function inquiry messagecontaining the FID (02) is sent from the external tool 63 (illustratedby the two-dot chain arrow Y1), the function inquiry response messagesare sent from the ECUs 2 and 10 to the external tool 63 (see the dashedarrows Y10 and Y11 in FIG. 8). Then, after receiving all of the functioninquiry response messages sent from the ECUs 2 and 10, the CPU 63 a ofthe external tool 63 creates the list in which the UIDs included in allof the response messages are recited (see (4) in FIG. 5). For example,in the case where the target function is the second function, the UIDs(02, 04, and 05) of the ECUs 2, 4, and 5 in which the second function isinstalled in advance can be automatically recited in the created list.

As described above, in the vehicle communication system SB according tothe fifth embodiment, in addition to the effects obtained by the thirdembodiment, either the gateway ECU 10 or the gateway ECU 20 linked tothe top-level communication bus 51A is configured to respond thefunction inquiry message sent from the external tool 63 in place of atleast one ECU in which the target function is installed beforehand andlinked to a communication bath lower in level than the communication bus51A.

Specifically, at least one ECU in which a target function is installedbeforehand and linked to a communication bath lower in level than thecommunication bus 51A requires no responding a function inquiry messagecontaining the FID of the target function.

This makes it possible to further reduce the communication load via thecommunication network 50A and the communication processing load of eachof the ECUs.

In addition, reduction of the communication load through thecommunication network 50A also can shorten a period from when theexternal tool 63 sends the function inquiry message until when itreceives the function inquiry response message corresponding to the sentfunction inquiry message. This makes it possible to further reduce thetime for the external tool 63 to identify at least one ECU installedwith the target function.

Sixth Embodiment

A vehicle communication system SC according to a sixth embodiment of thepresent invention will be described hereinafter with reference to FIG.10.

As compared to the structure of the vehicle communication system SBaccording to the fifth embodiment, the vehicle communication systemaccording to the sixth embodiment has two different points as follows.

Specifically, as the first different point, the vehicle communicationsystem SC includes an ECU 9 in addition to the ECUs 1 to 8, 10, 20, 30,and 40. The ECU 9 is linked to the first communication bus 51A. In theECU 9, a ninth function for vehicle control assigned with an FID equalto 09 is installed beforehand. The ECU 9 stores therein beforehand thecorresponding UID and the FID (09) of the ninth function. The ECU 9 willbe referred to as “master ECU 9” hereinafter.

As the second different point, the CPU 63 a of the external tool 63 isprogrammed to send a function inquiry message containing the FID of atleast one target function to only the master ECU 9 (see the two-dotchain arrow Y20 in FIG. 10).

When receiving the function inquiry message sent from the external tool63, the master ECU 9 is configured to:

send the received function inquiry message to the remaining ECUs of thesystem SC,

receive a function inquiry response message sent from at least one EC;and

send the received function inquiry response message to the external tool63 (see the dashed arrow Y21 in FIG. 10).

Except for the different points set forth above, the vehiclecommunication system of the sixth embodiment has substantially the samestructure as that of the vehicle communication system of the fifthembodiment. For this reason, like reference characters are assigned tolike parts in the vehicle communication systems according to the fifthand sixth embodiments so that descriptions of the parts of the vehiclecommunication system of the sixth embodiment will be omitted.

According to the configuration of the vehicle communication system SC,when the function inquiry message containing the FID (02) of the secondfunction as the target function is sent from the external tool 63 to themaster ECU 9, the master ECU 9 receives the function inquiry message.Next, the master ECU 9 sends the received function inquiry message toeach of the ECUs 1, 2, 0, and 20 linked to the first communication bus51A.

As a result, like the fifth embodiment (see FIG. 8), each of the ECUs 2and 10 sends the function inquiry response message to the master ECU 9.The master ECU 9 receives the function inquiry response message sentfrom each of the ECUs 2 and 10, and sends it to the external tool 63.

Specifically, the master ECU 9 according to the sixth embodiment isconfigured to relay a function inquiry message sent from the externaltool 63 to the remaining ECUs, and to relay a function inquiry responsemessage sent from at least one ECU to the external tool 63.

The external tool 63 therefore only communicates with the master ECU 9in order to identify at least one ECU in which a target function isinstalled beforehand. This makes it possible to reduce the communicationprocessing load of the external tool 63. In addition, it is. unnecessaryfor the master ECU 9 to have an FID-UID table, making it possible toprevent the resources of the master ECU 9 for use in data storage fromincreasing.

Note that, in the sixth embodiment, the master ECU 9 can be configuredto execute the actions (2) and (3) in FIG. 5 like the remaining ECUs.

Specifically, when a function inquiry message containing the FID (09) ofthe ninth function as the target function is sent from the external tool63 to the master ECU 9, the master ECU 9 is configured to:

receive the function inquiry message to send it to each of the ECUs 1,2, 0, and 20 linked to the first communication bus 51A; and

send a function inquiry response message containing its own UID (09) tothe external tool 63.

Seventh Embodiment

A vehicle communication system according to a seventh embodiment of thepresent invention will be described hereinafter. As compared to thestructure of the vehicle communication system S according to the firstembodiment, the CPU 63 a of the external too 63 is specially configuredto:

communicate with a specified ECU; and

identify, based on the communicated result, at least one ECU in which atarget function is installed beforehand, in other words, at least oneECU to which a request message for diagnosis monitoring should be sent.In the seventh embodiment, the memory card 65 need not necessarily beremovable from the external tool 63.

Except for the different points set forth above, the vehiclecommunication system of the seventh embodiment has substantially thesame structure as that of the vehicle communication system of the firstembodiment. For this reason, like reference characters are assigned tolike parts in the vehicle communication systems according to the firstand seventh embodiments so that descriptions of the parts of the vehiclecommunication system of the seventh embodiment will be omitted.

In addition, in the seventh embodiment, like the second to sixthembodiments, each of the ECUs stores therein beforehand its own UID andthe FID of at least one function installed therein.

In the seventh embodiment, one of the ECUs, such as the ECU 7 forexample, selves as a master ECU as the specified ECU.

Next, operations of the vehicle communication system according to theseventh embodiment will be described hereinafter with reference to FIG.11. FIG. 11 is a sequence diagram schematically illustrating thesequence of actions to be executed by the external tool 63 and each ECUand of communications sent therebetween.

When the power supply system PS starts to supply power to each of theECUs in response to an activate signal being input thereto, each of thenon-gateway ECUs 1 to 6 except for the master ECU 7 and gateway ECU 10informs the master ECU 7 about a function registration message. Thefunction registration message contains the own UID of each of the ECUs 1to 6 and the FID of at least one function installed in each of the ECUs1 to 6 (see (1) in FIG. 11). In other words, each of the non-gatewayECUs 1 to 6 informs the master ECU 7 about a function registrationmessage containing a UID and at least one FID that should be notified tothe master ECU 7.

When the power supply system starts to supply power to the ECUs, themaster ECU 7 receives the function registration messages informed fromthe non-gateway ECUs 1 to 6, and creates an FID-UID table T illustratedin, for example, FIG. 3 based on the received function registrationmessages (see (2) in FIG. 11).

As well as the first and second embodiments, the FID-UID table T isdesigned to represent each function is installed in advance in what UIDof the communicable ECUs. More simply, the FID-UID table T is designedto represent which functions are installed in advance in whichcommunicable ECUs.

Note that, in the seventh embodiment, because the ECU 10 is designedspecially for gateway, the ECU 10 is designed not to send a functionregistration message. If the FID of at least one function is installedin advance in the ECU 10, in other words, the ECU 10 has a function forvehicle control, the ECU 10 can be designed to send a functionregistration message containing its own UID and the FID of at least onefunction installed in advance therein.

Note that, in the seventh embodiment, the function registration messagesto be sent to the master ECU 7 from the non-gateway ECUs 1 to 6 at thestart of power supply include at least a header field and a data field.To the header field of the message, identification informationrepresenting that this message is a function registration message isarranged. The identification information allows the master ECU 7 tosecurely and simply distinguish between the function registrationmessages and normal communication messages.

Thereafter, while electrical connection between the communicationnetwork 50 and the external tool 63 through the connector 61 isestablished, an operator manipulates the keyboard or the data entryscreen of the input and display unit 63 e of the external tool 63 toenter an FID corresponding to at least one of the functions as a targetfor diagnosis monitoring.

In addition to the FID entry, the operator manipulates the keyboard orthe data entry screen of the input and display unit 63 e to enterdescriptions that are to instruct a corresponding ECU on what theoperator wants to monitor and diagnose regarding the target function.

Upon entry of the FID and the descriptions of the diagnosis monitoring,the CPU 63 a of the external tool 63 creates a function inquiry messagecontaining the FID corresponding to the target function, thereby sendingit to the master ECU 7 (see (3) in FIG. 11). For example, in the seventhembodiment, the function inquiry message includes the FID (03) of thethird function as the target function.

When receiving the function inquiry message, the master ECU 7 searchesthe FID-UID table T created by the action (2) in FIG. 11 for at leastone UID of an ECU in which the FID contained in the function inquirymessage is installed (see (4) in FIG. 11). When retrieving at least oneUID corresponding to the FID contained in the function inquiry messagefrom the FID-UID table T, the master ECU 7 creates a function inquiryresponse message containing the retrieved at least one UID, therebysending it to the external tool 63 (see (5) in FIG. 11).

In the ninth embodiment, the function inquiry message containing the FID(03) corresponding to the third function (target function) is sent fromthe external tool 63 to the master ECU 7. For this reason, the functioninquiry response message containing the UID (04) of the ECU 4 in whichthe third function is installed in advance is sent from the master ECU 7to the external tool 63.

The CPU 63 a of the external tool 63 receives the function inquiryresponse message sent from the master ECU 7, and creates a list of atleast one UID contained in the received function inquiry responsemessage, which is the same task as that in step S130 of FIG. 2 (see (4)in FIG. 11). Specifically, the created list recites at least one ECU inwhich the target function is installed.

Then, the CPU 63 a of the external tool 63 executes the same tasks instep S140 and S150 in FIG. 2, and thereafter sends the request messageto the ECU corresponding to at least one UID recited in the list createdby the action (6) in FIG. 11 (see (7) in FIG. 11).

Note that, in the seventh embodiment, as the request message sent fromthe external tool 63 to the ECU 4 by the action (7) in FIG. 11, a driverequest message that requests the ECU 4 to execute a function offorcibly driving an actuator that is a control target of the ECU 4 isillustrated by an example.

Specifically, upon receipt of the drive request message, the ECU 4executes a function of forcibly driving the actuator; this function isidentified by the drive request message, which causes the actuator toput in-vehicle devices into automatic action, such as force or motion(see (8) in FIG. 11). The operator therefore can monitor and diagnosethe operating state of each of the in-vehicle devices to determinewhether the target function (actuator driving function) is normal orabnormal based on the monitored and diagnosed result.

As described above, in the vehicle communication system according to theseventh embodiment, like the third embodiment, it is unnecessary for theexternal tool 63 to create and hold an FID-UID table in which therelationship between the FIDs of all of the functions and the UIDs ofall of the ECUs are recorded in advance. This makes it possible toreduce the processing load required to create the FID-UID table and thestorage capacity in the internal memory 63 c required to store theFID-UID table.

In addition, the external tool 63 only communicates with the master ECU7 in order to identify at least one ECU in which a target function isinstalled beforehand, making it possible to reduce the communicationprocessing load of the external tool 63.

Note that, in the seventh embodiment, as a modification, the master ECU7 can create an FID-UID table when a function inquiry message sent fromthe external tool 63 is received in place of when power supply isstarted.

Specifically, when receiving the function inquiry message sent from theexternal tool 63, the master ECU 7 sends, to the remaining ECUs, afunction check request message inquiring, to each of the remaining ECUswhich functions are installed therein.

When a function acknowledge message that contains its own UID and theFID of at least one function installed in each ECU is sent therefrom,the master ECU 7 receives the function acknowledge messages sent fromthe remaining ECUs, and creates an FID-UID table T illustrated in, forexample, FIG. 3 based on the received function acknowledge messages.

As compared to the modification set forth above, the configurationillustrated in FIG. 11 in which the master ECU 7 is designed to createan FID-UID table when power supply is started to each ECU has anadvantage. This is because of shortening a period from when the externaltool 63 sends the function inquiry message until when it receives thefunction inquiry response message corresponding to the sent functioninquiry message.

Eighth Embodiment

A vehicle communication system according to an eighth embodiment of thepresent invention will be described hereinafter. As compared to thestructure of the vehicle communication system S according to the firstembodiment, how to communicate between the external too 63 and each ECUaccording to the eighth embodiment is different from that according tothe first embodiment.

In the eighth embodiment, the memory card 65 need not necessarily beremovable from the external tool 63.

Except for the different points set forth above, the vehiclecommunication system of the eighth embodiment has substantially the samestructure as that of the vehicle communication system of the firstembodiment. For this reason, like reference characters are assigned tolike parts in the vehicle communication systems according to the firstand seventh embodiments so that descriptions of the parts of the vehiclecommunication system of the eighth embodiment will be omitted.

Next, operations of the vehicle communication system according to theeighth embodiment will be described hereinafter with reference to FIG.12. FIG. 12 is a sequence diagram schematically illustrating thesequence of actions to be executed by the external tool 63 and each ECUand of communications sent therebetween.

While electrical connection between the communication network 50 and theexternal tool 63 through the connector 61 is established, an operatormanipulates the keyboard or the data entry screen of the input anddisplay unit 63 e of the external tool 63 to enter an FID correspondingto at least one of the functions as a target for diagnosis monitoring.

In addition to the FID entry, the operator manipulates the keyboard orthe data entry screen of the input and display unit 63 e to enterdescriptions that are to instruct a corresponding ECU on what theoperator wants to monitor and diagnose regarding the target function.

Upon entry of the FID and the descriptions of the diagnosis monitoring,the CPU 63 a of the external tool 63 creates a function inquiry messagecontaining the FID corresponding to the target function, thereby sendingit to each of the ECUs 1 to 7, and 10 (see (1) and (4) in FIG. 12). Notethat, like the first embodiment, the external tool 63 can be designedto, Upon entry of the descriptions of the diagnosis monitoring,automatically determine an FID of at least one function that meets theentered descriptions.

When receiving the request message, each of the ECUs 1 to 7, and 10determines whether the function corresponding to the FID contained inthe request message is installed therein (see (2) and (5) in FIG. 12).

If it is determined that the function corresponding to the FID containedin the request message is installed therein (the determination of theaction (2) or (5) is YES), an ECU executes a task indicated by therequest message sent from the external tool 63 (see (3) and (6) in FIG.12).

For example, the action (1) in FIG. 12 allows the external tool 63 tosend, as the request message for diagnosis monitoring, a dataacquisition request message containing the FID (01) of the firstfunction (target function) to each of the ECUs. For this reason, asillustrated by the action (3) in FIG. 12, each of the ECUs 1 and 2 inwhich the first function is installed beforehand executes a dataacquisition function (the target function) of:

acquiring control data that has been stored therein and specified in thedescriptions of the data acquisition request message;

creating a data acquisition response message with the data field towhich the acquired control data is arranged; and

returning the created data acquisition response message to the externaltool 63.

In addition, the action (4) in FIG. 12 allows the external tool 63 tosend, as the request message for diagnosis monitoring, an actuator driverequest message containing the FID (02) of the second function (targetfunction) to each of the ECUs. For this reason, as illustrated by theaction (6) in FIG. 12, the ECU 2 in which the second function isinstalled beforehand executes a function (target function) of forciblydriving the actuator indicated by the actuator drive request message.

As described above, according to the eighth embodiment, like each of thefirst to seventh embodiment, even if an operator to perform diagnosismonitoring of the target vehicle has no grasp where the target functionis installed in the ECUs, it is possible for the operator to performdiagnosis monitoring of the target function.

In the sixth to sixth embodiments illustrated in FIGS. 6 to 10, thecommunication network 50A can have a four or more level hierarchicalstructure.

In each of the first to eighth embodiments, the connector 61 canestablish electrical connection between the external tool 63 and thecommunication network 50, 50A in a vehicle, but the present invention isnot limited to the structure. Specifically, the external tool 63 and thecommunication network 50, 50A can establish wireless connectiontherebetween.

Specifically, a vehicle communication system further includes a radiocommunication control device that allows radio communication between theexternal tool 63 and each of the ECUs linked to the communicationnetwork 50, 50A. The radio communication control device need not beprovided as a hardware device. Specifically, a software module causingat least one ECU (gateway ECU or non-gateway ECU) to establish radiocommunications between the external tool 63 and each of the ECUs can beinstalled in the at least one ECU.

In each of the first to eighth embodiments, the first functions (FID=01)installed in both the ECUs 1 and 2 (UIDs=01 and 02) can be identical toeach other. On the other hand, the first functions (FID=01)distributedly installed in both the ECUs 1 and 2 (UIDs=01 and 02) can bedesigned to be collaborated with each other as a single function module.This allows the ECU 1 and/or 2 to execute the first functions, therebyactualizing execution of at least one task, such as an operation of aspecific control variable associated with vehicle control.

While there has been described what is at present considered to be theembodiments and their modifications of the present invention, it will beunderstood that various modifications which are not described yet may bemade therein, and it is intended to cover in the appended claims allsuch modifications as fall within the true spirit and scope of theinvention.

1. A vehicle communication system in which a plurality of control unitsare communicably linked to a communication network, and a monitoringdevice is designed to communicably linkable to the communication networkand to establish communications with at least one of the plurality ofcontrol units for monitoring, the vehicle communication systemcomprising: a first identifier uniquely assigned to at least onefunction for vehicle control, the at least one function being installedin at least one of the plurality of control units; and an identifyingunit configured to identify that a target function uniquely assignedwith a target identifier is installed in which of the control unitsbased on the first identifier and the target identifier.
 2. A vehiclecommunication system according to claim 1, wherein the at least onefunction includes a plurality of functions to each of which the firstidentifier is assigned, the plurality of functions being installed in atleast one of the plurality of control units, and the identifying unitfurther comprises: a table representing that each of the plurality offunctions is installed in which of the control units using the firstidentifier of each of the plurality of functions; and an identifyingmodule configured to search the table for the target function based onthe target identifier and to identify that the target function isinstalled in which of the control units based on the searched result. 3.A vehicle communication system according to claim 2, wherein theidentifying module is installed in the monitoring device, and themonitoring device further includes a memory unit removable thereto suchthat the table is stored in the memory unit, the identifying modulereading the table from the memory unit and searching the table for thetarget function.
 4. A vehicle communication system according to claim 1,wherein the at least one function includes a plurality of functions toeach of which the first identifier is assigned, the plurality offunctions being installed in at least one of the plurality of controlunits, and the identifying unit further comprises: a first sendingmodule provided in the monitoring unit and configured to send a functioncheck request message to each of the control units; a second sendingmodule provided in each of the control units and configured to send afunction acknowledge message to the monitoring device upon receiving ofthe function check request message, the function acknowledge messagecontaining the first identifier of at least one of the functionsinstalled in each of the control units and a second identifier uniquelyassigned with each of the control units; a table creating moduleprovided in the monitoring device and configured to create a tablerepresenting that each of the plurality of functions is installed inwhich of the control units based on the first identifier and the secondidentifier contained in the function acknowledge message sent from eachof the control units; and an identifying module provided in themonitoring device and configured to search the created table for thetarget function and to identify that the target function is installed inwhich of the control units based on the searched result.
 5. A vehiclecommunication system according to claim 4, wherein the identifying unitfurther comprises a broadcasting module provided in the monitoring unitand configured to broadcast a communication check request message toeach of the control units before the first sending module sends thefunction check request message, the communication check request messagecausing each of the control units to send a response to the monitoringdevice, the first sending module being configured to: determine whetherto receive the response from each of the control units within apredetermined period; and send the function check request message to atleast one of the control units when it is determined that the responsefrom the at least one of the control units is received within thepredetermined period after broadcasting the communication check requestmessage by the broadcasting module.
 6. A vehicle communication systemaccording to claim 1, wherein the at least one function includes aplurality of functions to each of which the first identifier isassigned, the plurality of functions being installed in at least one ofthe plurality of control units, and the identifying unit furthercomprises: a first sending module provided in the monitoring unit andconfigured to send a function inquiry request message to each of thecontrol units, the function inquiry request message containing the firstidentifier of the target function; a determining module provided in eachof the control units and configured to determine whether the targetfunction is installed in each of the control units upon receiving of thefunction inquiry request message; a second sending module provided in atleast one of the control units and configured to send a function inquiryresponse message when it is determined the target function is installedin the at least one of the control units, the function inquiry responsemessage containing a second identifier uniquely assigned with the atleast one of the control units, and an identifying module provided inthe monitoring device and configured to identify that the targetfunction is installed in the at least one of the control units based onthe second identifier contained in the function inquiry responsemessage.
 7. A vehicle communication system according to claim 6, whereinthe communication network includes: a first communication bus to whichthe monitoring device is communicably linkable; and a secondcommunication bus lower in level than the first communication bus andlinkable to the first communication bus via a gateway unit, one of thecontrol units serving as the gateway unit operative to interconnect thefirst and second communication buses, and the gateway unit is configuredto: communicate with at least one of the control units linked to thesecond communication bus to obtain identification informationrepresenting that the first identifier of at least one of the functionsinstalled in the at least one of the control units; create a list inwhich the obtained identification information has been recorded; andupon receiving of the function inquiry request message, relay thefunction inquiry request message to the at least one of the controlunits only when the first identifier contained in the function inquiryrequest message is recorded in the created list.
 8. A vehiclecommunication system according to claim 7, wherein the gateway unit isconfigured to execute, immediately after start of power supply to eachof the control units, the communication with the at least one of thecontrol units linked to the second communication bus to obtain theidentification information.
 9. A vehicle communication system accordingto claim 6, wherein the communication network includes; a firstcommunication bus to which the monitoring device is communicablylinkable; a second communication bus lower in level than the firstcommunication bus and linkable to the first communication bus via afirst gateway unit, one of the control units serving as the firstgateway unit operative to interconnect the first and secondcommunication buses; and a third communication bus lower in level thanthe second communication bus and linkable to the second communicationbus via a second gateway unit, another one of the control units servingas the second gateway unit operative to interconnect the second andthird communication buses, a least one of the control units linked tothe third communication bus is configured, in response to start of powersupply thereto, to inform the second gateway unit about firstidentification information representing that the first identifier of atleast one of the functions installed in the at least one of the controlunits, at least another one of the control units linked to the secondcommunication bus is configured, in response to start of power supplythereto, to inform the first gateway unit about second identificationinformation representing that the first identifier of at least one ofthe functions installed in the at least another one of the controlunits, the second gateway unit is configured, in response to start ofpower supply thereto, to: receive the first identification informationsent from the at least one of the control units linked to the thirdcommunication bus; create a list in which the obtained firstidentification information has been recorded; and inform the firstgateway unit about information including the first identificationinformation recorded by the list and the first identifier of at leastone of the functions installed in the second gateway unit, and the firstgateway unit is configured, in response to start of power supply to eachof the control units, to: receive the second identification informationsent from the at least another one of the control units and theinformation sent from the second gateway unit; and create a list inwhich the obtained second identification information and the informationsent from the second gateway unit has been recorded.
 10. A vehiclecommunication system according to claim 8, wherein the power supply isstarted in response to turning on of a vehicle ignition switch.
 11. Avehicle communication system according to claim 8, wherein the powersupply is started in response to turning on of a vehicle key switch attiming of insertion of a vehicle ignition key into a vehicle keycylinder.
 12. A vehicle communication system according to claim 7,wherein the gateway unit is configured to send a message to the at leastone of the control units linked to the second communication bus toobtain the identification information, and the message contains a headerfield to which identification information is arranged, theidentification information representing that the corresponding messageis a communication message used to create the list.
 13. A vehiclecommunication system according to claim 6, wherein the communicationnetwork includes: a first communication bus to which the monitoringdevice is communicably linkable; and a second communication bus lower inlevel than the first communication bus and linkable to the firstcommunication bus via a gateway unit, one of the control units servingas the first gateway unit operative to interconnect the first and secondcommunication buses, and the gateway unit is configured to: communicatewith at least one of the control units linked to the secondcommunication bus to obtain identification information representing thatthe first identifier of at least one of the functions installed in theat least one of the control units and the second identifier of the atleast one of the control units; create a table in which the firstidentifier and the second identifier contained in the obtainedidentification information are recorded to be associated to each other,when at least one function is installed in the gateway unit, the firstidentifier of the at least one function installed in the gateway unitand the second identifier of the gateway unit being recorded to beassociated with each other in the table; upon receiving of the functioninquiry request message, determine whether the first identifiercontained in the function inquiry request message is recorded in thecreated table; and send a function inquiry response message to themonitoring unit when it is determined that the first identifiercontained in the function inquiry request message is recorded in thecreated table, the function inquiry response message containing thesecond identifier corresponding to the first identifier contained in thefunction inquiry request message.
 14. A vehicle communication systemaccording to claim 13, wherein the gateway unit is configured toexecute, immediately after start of power supply to each of the controlunits, the communication with the at least one of the control unitslinked to the second communication bus to obtain the identificationinformation.
 15. A vehicle communication system according to claim 6,wherein the communication network includes: a first communication bus towhich the monitoring device is communicably linkable; a secondcommunication bus lower in level than the first communication bus andlinkable to the first communication bus via a first gateway unit, one ofthe control units serving as the first gateway unit operative tointerconnect the first and second communication buses; and a thirdcommunication bus lower in level than the second communication bus andlinkable to the second communication bus via a second gateway unit,another one of the control units serving as the second gateway unitoperative to interconnect the second and third communication buses, aleast one of the control units linked to the third communication bus isconfigured, in response to start of power supply thereto, to inform thesecond gateway unit about identification information representing thatthe first identifier of at least one of the functions installed in theat least one of the control units and the second identifier of the atleast one of the control units, at least another one of the controlunits linked to the second communication bus is configured, in responseto start of power supply thereto, to inform the first gateway unit aboutsecond identification information representing that the first identifierof at least one of the functions installed in another at least one ofthe control units and the second identifier of another at least one ofthe control units, the second gateway unit is configured, in response tostart of power supply thereto, to: receive the first identificationinformation sent from the at least one of the control units linked tothe third communication bus; create a first table in which the firstidentifier and the second identifier contained in the obtainedidentification information are recorded to be associated to each other,when at least one function is installed in the second gateway unit, thefirst identifier of the at least one function installed in the secondgateway unit and the second identifier of the second gateway unit beingrecorded to be associated with each other in the first table; and informthe first gateway unit about table creating information includinginformation representing the created first table, and the first gatewayunit is configured, in response to start of power supply to each of thecontrol units, to: receive the second identification information sentfrom the at least another one of the control units and the tablecreating information sent from the second gateway unit; create a secondtable in which the first identifier and the second identifier containedin the table creating information are recorded to be associated to eachother, when at least one function is installed in the first gatewayunit, the first identifier of the at least one function installed in thefirst gateway unit and the second identifier of the first gateway unitbeing recorded to be associated with each other in the second table;upon receiving of the function inquiry request message, determinewhether the first identifier contained in the function inquiry requestmessage is recorded in the created second table; and send a functioninquiry response message to the monitoring unit when it is determinedthat the first identifier contained in the function inquiry requestmessage is recorded in the created second table, the function inquiryresponse message containing the second identifier corresponding to thefirst identifier contained in the function inquiry request message. 16.A vehicle communication system according to claim 14, wherein the powersupply is started in response to turning on of a vehicle ignitionswitch.
 17. A vehicle communication system according to claim 14,wherein the power supply is started in response to turning on of avehicle key switch at timing of insertion of a vehicle ignition key intoa vehicle key cylinder.
 18. A vehicle communication system according toclaim 13, wherein the gateway unit is configured to send a message tothe at least one of the control units linked to the second communicationbus to obtain the identification information, and the message contains aheader field to which identification information is arranged, theidentification information representing that the corresponding messageis a communication message used to create the table.
 19. A vehiclecommunication system according to claim 13, wherein the first sendingmodule is configured to send the function inquiry request message to oneof the control units linked to the first communication bus in place ofeach of the control units, and the one the control units is configuredto: send the function inquiry message to the remaining control units;receive the function inquiry response message sent from the at least oneof the control units when it is determined the target function isinstalled in the at least one of the control units, the function inquiryresponse message containing a second identifier uniquely assigned withthe at least one of the control units; and send the received functioninquiry response message to the monitoring device.
 20. A vehiclecommunication system according to claim 1, wherein the at least onefunction includes a plurality of functions to each of which the firstidentifier is assigned, the plurality of functions being installed in atleast one of the plurality of control units, and the identifying unitfurther comprises: a table provided in one of the control units andrepresenting that each of the plurality of functions is installed inwhich of the control units using the first identifier of each of theplurality of functions; a first sending module provided in themonitoring unit and configured to send a function inquiry requestmessage to the one of the control units, the function inquiry requestmessage containing the first identifier of the target function; asearching module provided in the one of the control units and configuredto search the table for at least one of the control units correspondingto the target function contained in the function inquiry requestmessage; a second sending module provided in the one of the controlunits and configured to send, to the monitoring unit, a function inquiryresponse message containing a second identifier uniquely assigned to theat least one of the control units; and an identifying module provided inthe monitoring device and configured to identify that the targetfunction is installed in the at least one of the control units whosesecond identifier is contained in the function inquiry response message.21. A vehicle communication system according to claim 20, wherein eachof the control units except for the one of the control units isconfigured, in response to start of power supply thereto, to inform theone of the control units about the first identifier of at least one ofthe function installed therein and the second identifier of each of thecontrol units except for the one of the control units, and the one ofthe control units is configured, in response to start of power supplythereto, to create the data table based on the first identifier of atleast one of the functions installed in each of the control units exceptfor the one of the control units.
 22. A vehicle communication systemaccording to claim 21, wherein the power supply is started in responseto turning on of a vehicle ignition switch.
 23. A vehicle communicationsystem according to claim 21, wherein the power supply is started inresponse to turning on of a vehicle key switch at timing of insertion ofa vehicle ignition key into a vehicle key cylinder.
 24. A vehiclecommunication system according to claim 21, wherein each of the controlunits except for the one of the control units is configured to send amessage to the one of the control units, and the message contains aheader field to which identification information is arranged, theidentification information representing that the corresponding messageis a communication message used to create the table.
 25. A vehiclecommunication system according to claim 1, wherein the at least onefunction includes a plurality of functions to each of which the firstidentifier is assigned, the plurality of functions being installed in atleast one of the plurality of control units, and the identifying unitfurther comprises: a sending unit provided in the monitoring device andconfigured to send a request message to each of the control units, therequest message containing the first identifier of the target functionand descriptions used to monitor the target function; and a determiningunit provided in each of the control units and configured to: receivethe request message; determine whether the target function whose firstidentifier is contained in the request message is installed therein; andexecute the target function based on the descriptions correspondingthereto when it is determined that the target function whose firstidentifier is contained in the request message is installed therein. 26.An electronic control unit installed in a vehicle and designed tocontrol the vehicle, the control unit being communicably linked to acommunication network installed in the vehicle and communicably linkablethrough the communication network to a monitoring device designed toestablish communications with at least one of the plurality of controlunits for monitoring, the electronic control unit comprising: at leastone function for vehicle control uniquely assigned with an identifierand installed therein; a receiving unit configured to receive a requestmessage sent from the monitoring device, the request message containingthe identifier of a target function and descriptions used to monitor thetarget function; a determining unit configured to determine whether thetarget function whose identifier is contained in the request message isinstalled therein; and an executing unit configured to execute thetarget function based on the descriptions corresponding thereto when itis determined that the target function whose identifier is contained inthe request message is installed therein.
 27. A system including amonitoring unit and a plurality of executing units in at least one ofwhich a plurality of functions to be executed thereby are installed, theplurality of executing units being communicably linked to acommunication network, the monitoring device being designed to establishcommunications with the plurality of executing units for monitoring, thesystem comprising: a first identifier uniquely assigned to each of theplurality of functions; a second identifier uniquely assigned to each ofthe plurality of control units, and an identifying unit configured toidentify that a target function uniquely assigned with a targetidentifier is installed in which of the control units based on arelationship between the first identifier, the second identifier, andthe target identifier.
 28. A vehicle communication method between aplurality of control units and a monitoring device, the plurality ofcontrol units being communicably linked to a communication network, themonitoring device being designed to communicably linkable to thecommunication network and to establish communications with at least oneof the plurality of control units for monitoring, the vehiclecommunication method comprising: providing a first identifier uniquelyassigned to at least one function for vehicle control, the at least onefunction being installed in at least one of the plurality of controlunits; and identifying that a target function uniquely assigned with atarget identifier is installed in which of the control units based onthe first identifier and the target identifier.